Located nearly 2,000 miles below the surface of the Earth, the core mantle boundary (CMB) represents one of the most dramatic layers within our planet (second only to Earth's surface). Changes across the layer exert a primary influence on the cooling of the Earth, the dynamics of the core (and hence Earth's protective magnetic field), and on the dynamics of the mantle (expressed as plume-related volcanism at the Earth's surface). We aim to answer the question, how do physical and chemical processes in the core-mantle boundary region modulate the planet's mass and heat flux, and what are the consequences for the whole Earth system? This layer is not just physically remote, but the conditions there are extremely challenging to reproduce experimentally: pressures over one million times atmospheric and temperatures approaching 6000 degrees Fahrenheit. Although, enormous strides have been made in recent decades towards understanding the dynamics of the deep Earth system using techniques from different disciplines (e.g., geodynamics, seismology, mineral physics), no single method provides a unique answer. Consequently, the project will combine data, methods, and expertise to attempt to overcome this non-uniqueness. The project will support (at least partially) three graduate students working in our multi-disciplinary environment; the students involved with this work will individually become exposed to state-of-the-art skills that can be applied within the Earth sciences and more broadly in science and engineering.
Major advances in experimental and computational facilities, instrument resolution, and deployment of the USArray are providing unprecedented opportunities to understand the processes operating in the deep Earth. However, we lack a comprehensive knowledge of how the deepest parts of the Earth operate within the global Earth system. The project will encompass comprehensive laboratory measurements, ab-initio calculations, seismic observations, and 4-D models. We will develop an integrated multi-scale understanding of the chemical and physical processes at the boundary between solid mantle and fluid core which couple across spatial and temporal scales, while improving data resolution and modeling capabilities to better predict the evolution of the earth system. We will apply seismic modeling techniques to better constrain the structure of the mantle and we will mine and model seismic waveform data from regional arrays (US, Chinese and Japanese seismic networks). A host of forward 2-D and spherical dynamic models linked to a new paleogeographic system will be used to predict and interpret seismic data. We will perform laboratory experiments under high-PT and determine elastic properties and equations of state of candidate phases. The geodynamic and seismic models will use the best constraints from mineral physics, including our experimental work.
